I found an Eastern European food stand located in the basement of St. Lawrence Market, close to the public washrooms. It's probably a tourist trap but until I find another this is my go to place for now. They serve a wide selection of comfort dishes at reasonable prices from pierogi, knish, latke, cabbage rolls & blintzes just to name a few.
I sampled their pierogi, potato & cheese, and they were filling for a light breakfast. It's served with a dollop of sour cream if you want but at home I usually put ranch dressing on it. I know I'm weird. They also make veal pierogi or pelmeni as they're known in Russia and dessert pierogi, which I may sample later today maybe. Definitely a place to check out whenever you're visiting the Market.